The construction industry in the United States, particularly the residential construction industry has changed dramatically over the last few decades. There was once a time when it was said that labor was cheap, and materials were expensive. It has recently become axiomatic that labor is expensive and materials are cheap. Therefore, a wide variety of labor saving tools and devices have become available to the construction industry. The inventor herein is also the inventor of a variety of labor saving devices directed to the construction trades including U.S. Pat. No. 6,708,461 titled “Pinch Clamp” issued Mar. 23, 2004; U.S. Pat. No. 6,715,374 titled “Cabinet and Mill Work Finish Bar” issued Apr. 4, 2004 and pending U.S. patent application Ser. No. 11/013,129 titled “Repetitive Fence for Cross Cutting Materials” filed Dec. 15, 2004. The disclosure of those patents/applications are incorporated herein by reference.
Particularly with respect to the installation of drywall in residential construction, it has been recognized that there is a need to facilitate the installation of drywall on vertical framing studs. Today, drywall is physically connected to studs by the use of drywall screws, with electric drills/screwdrivers rather than with nails. That is, the drywall installer typically positions a sheet of drywall (i.e. sheet rock) against the internal surface of framing studs. The installer may then locate the studs behind the drywall using a variety of techniques including prescribed measurements or a so-called “stud finder” tool. Stud finder tools comprise of a wide variety of devices but are typically of the sonic variety defined by a handheld device having a planar surface for sliding over the surface of the drywall. A sonic sensor indicates the existence of a stud behind the drywall by actuating an indicator (either visual or audible or both). The drywall installer may then mark this position, or promptly drill a hole with an electric drill, position a drywall screw in the resulting countersunk hole, and drive the screw home with the same drill. The predrilling step may be eliminated if the electric drill is of the type having a clutch allowing the screw head to be set flush with the drywall surface. Finally, in a process called taping and mudding, the drywall screw head is concealed as are joints between drywall sections. The rechargeable electric drill has become a favorite tool amongst drywall installers. Almost invariably, a rechargeable battery pack is either concealed within or connected to a handle of the portable electric drill.
In order to facilitate rapid location of studs behind drywall, and subsequent installation of drywall screws, various prior art devices have been conceived which incorporate a stud finding device, or other object sensor into the body of the electric drill. U.S. Patent Application No. U.S. 2001/0053313A1 published on Dec. 20, 2001 titled “Hand Drill Attachment” discloses a subsurface object locator which is removably attached to the top of a battery powered electric drill. The removable subsurface object locator is readily detached from the drill for application against a surface to detect a subsurface object, such as a framing stud. The use of the device described in this published application requires a series of steps by the user to remove the subsurface object locator from the drill, position the object locator against the wall, mark the location of the stud, reattach the subsurface object locator to the drill and use the drill to install the drywall screw into the wall. While such a device no longer requires that a drywall installer carry a separate stud finder in a pocket, use of this device remains cumbersome.
Published European Patent Application EP1,595654A1 titled “Handheld Tool with Removable Object Sensor” filed on Apr. 27, 2005 and claiming a priority from U.S. application Ser. No. 09/933,177 filed Nov. 16, 2001 having the same title attempts to remedy the shortcomings of the aforementioned '313 published U.S. Patent Application. In the European Patent Application, a battery powered electric drill includes a removable object sensor, such as a stud locator in a variety of positions with respect to the drill for easy removal thereof. Nevertheless, the device disclosed in the European Patent Application still requires that the user employ a multi-step process for removing the object sensor from the tool, using the object sensor, and then returning the object sensor to the tool prior to subsequent operation of the electric drill for placement of a drywall screw through drywall into a stud. It is difficult to conceive that a user might use the device disclosed in the European Patent Application without using two hands, or removing his or her hand from an operating position of the drill.
Therefore, a need exists for a combination power tool and object sensor which permits a user to locate an object, such as a framing stud beneath a sheet of drywall without removing the object sensor from the power tool.
A further need exists, for a combination power tool and object sensor in which the object sensor can be operated without the requirement of the user removing his or her hand from a power tool operating position.